Hall sensor

ABSTRACT

A Hall sensor including multiple Hall elements which have a first terminal contact and a second terminal contact and a third terminal contact, the multiple Hall elements being electrically connected in series. The first terminal contacts and the third terminal contacts of the individual Hall elements are connected to each other, and the second terminal contacts of the Hall elements are supply voltage terminals or as Hall voltage taps. A beginning of a first branch being electrically connected in series to an end of a second branch, in such a way that the direction of the current flow through the Hall elements of the first branch is counter to the direction of the current flow through the Hall elements of the second branch.

This nonprovisional application claims priority under 35 U.S.C. §119(a)to German Patent Application No. 10 2014 007 208.8, which was filed inGermany on May 19, 2014, and which is herein incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a Hall sensor.

2. Description of the Background Art

Vertical Hall sensors are known from the European patent application EP9 540 85, which corresponds to U.S. Pat. No. 6,542,068, as well as fromDE 101 50 955 C1, in which multiple electrically conductive regionsextend perpendicularly to the surface of a substrate and into thesubstrate for the purpose of forming multiple Hall elements and whichhave multiple connecting regions of a side face on the surface of thesubstrate. Hall sensors are used in many technical areas, e.g., todetect the position of switches or actuators contactlessly and thus freeof wear. In this area, the use and spatial detection of magnetic fieldsoffer advantages over an optical or mechanical detection, sincetechnologies based on magnetic fields, like those used in Hall sensors,are much less sensitive to contaminants than are optical methods.

A Hall sensor is known from DE 10 2011 107 767 A1, which corresponds toUS 20130015853, which is incorporated herein by reference, and whichshows four series-connected Hall elements, which are particularlysuitable for reducing influences of offset voltages with the aid of thespinning current method.

In connection with lateral Hall sensors for suppressing the offset ofthe sensor signal, the spinning current method is known from the booktitled “Rotary Switch and Current Monitor by Hall-Based Microsystems” bythe author Ralph Steiner Vanha, Verlag Physical Electronics Laboratory,Swiss Federal Institute of Technology (ETH) Zurich, 1999, pages 39-53.In the spinning current method, the measurement and current directionsat the Hall sensor are continuously further rotated in cycles by, forexample, 90° at a certain clock frequency and summed up over allmeasuring signals of a full rotation by 360°, thereby reducing theinfluence of offset voltages.

A series arrangement of Hall element having three terminal contacts isfurthermore known from EP 2049910 B1, which corresponds to U.S. Pat. No.9,024,622, which illustrates two Hall elements being connected inparallel in each case. To carry out a calibration, a wire through whichcurrent flows is guided over the Hall elements.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a devicewhich refines the prior art.

According to an embodiment of the invention, a Hall sensor having anincreased magnetic sensitivity is provided, the Hall sensor includingmultiple Hall elements, and each of the Hall elements including a firstterminal contact and a second terminal contact and a third terminalcontact, and the multiple Hall elements being electrically connected inseries. The first terminal contacts and the third terminal contacts ofthe individual Hall elements are connected to each other, the secondterminal contacts of the Hall elements being designed as supply voltageterminals or as Hall voltage taps, and the particular second terminalcontact of the Hall element being designed as the middle contact of theHall element, and a first branch being provided with a first beginningand a first end and, in this connection, the first branch including aseries circuit of a first plurality of Hall elements and/or parts ofHall elements, and a second branch being provided with a secondbeginning and a second end and, in this connection, the second branchincluding a series circuit of a second plurality of Hall elements and/orparts of Hall elements, and the two branches being electricallyconnected in series, in this connection the end of the first branchbeing electrically connected in series to the beginning of the secondbranch, and the beginning of the first branch being electricallyconnected in series to the end of the second branch in such a way thatthe direction of the current flow through the Hall elements of the firstbranch is counter to the direction of the current flow through the Hallelements of the second branch, so that a vector product J1×B=−(J2×B) isfulfilled, where J1 is the current density vector in the Hall elementsof the first branch, and J2 is the current density vector in the Hallelements of the second branch, and B is the vector of an appliedmagnetic field, and a total of at least four Hall voltage taps areprovided in the two branches, two of the Hall voltage taps beingdisposed in the first branch and two of the Hall voltage taps beingdisposed in the second branch, and the Hall voltage taps being designedas middle contacts.

The two branches can be electrically connected in such a way that aclosed ring is formed from, for example, closely spatially adjacent Hallelements. The algebraic sign of the component of the Hall voltage to bemeasured, induced by an applied magnetic field, can depend on thedirection of the current flow and on the direct of the adjacent magneticfield and on the doping of the semiconductor regions in which thesemiconductor elements are provided. Therefore, the algebraic signs ofthe component of the Hall voltages induced by an applied magnetic fieldand ascertained at the middle contacts of the Hall elements of the firstbranch can be provided opposite the corresponding components of the Hallvoltages ascertained at the middle contacts of the Hall elements of thesecond branch.

In the first branch, at least two Hall elements each have a Hall voltageof a first identical polarity, and in the second branch, at least twoHall elements also each have a Hall voltage of a polarity which isopposite the first polarity, at least two differences of Hall voltagesmay be ascertained with the aid of an advantageous interconnection ofthe middle contacts of the Hall elements, and the two differences may beadded up. With a given operating current, the Hall voltage of the Hallsensor is therefore derived as the sum of at least two differences,ascertained at the four associated Hall voltage taps. In other words, aHall voltage of the Hall sensor, the Hall voltage of the Hall sensorbeing referred to below as the so-called total Hall voltage, isascertained from the sum of Hall voltage differences or, in other words,from the sum of Hall voltage difference signals, each Hall voltagedifference being derived from a difference formation of the Hall voltageat one of the middle contacts of a Hall element of the first branch andthe Hall voltage at one of the middle contacts of a Hall element of thesecond branch. The following generally applies to Hall voltageV_(HSensor) of the Hall sensor or, in other words, the following appliesto the total Hall voltage with an even number n of Hall voltage taps:

$V_{HSensor} = {\sum\limits_{i = 1}^{n/2}\; \left( {V_{H + i} - V_{H - i}} \right)}$

where V_(H+i) represents the Hall voltages ascertained at the middlecontacts of the Hall elements of the first branch, and V_(H−i)represents the Hall voltages ascertained at the middle contacts of theHall elements of the second branch. Studies have shown that the number nis an even number. It has furthermore been demonstrated that thefollowing applies:

N−2≦n≦N

where:

N=N1+N2

and N is the total number of Hall elements in the two branches and N1 isa first plurality of Hall elements and/or parts of Hall elements and N2is a second plurality of Hall elements and/or parts of Hall elements. Nis a positive integer in this case. In this connection, N1 and N2 arefurthermore each a positive integer or half-integer.

Magnetic sensitivity S_(A) is furthermore derived from the followingrelation:

$S_{A} = {{V_{HSensor}/B} = {{1/B}{\sum\limits_{i = 1}^{n/2}\; \left( {V_{H + i} - V_{H - i}} \right)}}}$

i.e., the magnetic sensitivity increases along with the increase in thenumber n of Hall voltage taps in the two branches, without an increasein the current flow through the series-connected Hall elements with aconstant voltage supply. According to the invention, the otherwisecommon loading of the Hall sensors by an increased current forincreasing the magnetic sensitivity may be reduced hereby, and theinterfering influences, in particular as a result of heating, may bedecreased.

In an embodiment, the first terminal contacts and the third terminalcontacts are disposed symmetrically around the second terminal contact.Studies have shown that it is particularly advantageous when the Hallelements as a whole have an identical structure and, in particular, asubstantially identical layout. One advantage is that the influence ofinterference due to direct current magnetic fields, and of offsetvoltages of the individual Hall elements may be reduced and thesensitivity of the Hall sensor increased with the aid of the symmetry ofthe Hall elements with respect to each other and the symmetry of the twobranches with respect to each other, in combination with the oppositecurrent direction in the first branch compared to the second branch.

With the aid of the symmetrical arrangement of the first terminalcontacts and the third terminal contacts around the second terminalcontacts, it can be ensured that the first terminal contact and thethird terminal contact have an essentially identical design and arecorrespondingly disposed on both sides of the second terminal contact,i.e., each are disposed at the same distance from the particular secondterminal contact. A symmetry plane thus passes through the secondterminal contact with respect to the arrangement of the first terminalcontact and the third terminal contact. A differentiated influence ofthe first terminal contacts and the third terminal contacts on thesecond terminal contacts, and thus on the Hall voltage, is reducedhereby. Slight, in particular manufacturing-induced, differences in theshape, material, size or relative arrangement between the first terminalcontacts and the third terminal contacts surprisingly play a secondaryrole in the overall evaluation of the series-connected Hall elements.

In an embodiment, the first branch and the second branch are disposedparallel to a shared straight line or along two different straight linesor along multiple straight lines, wherein the two or the multiple, i.e.,the more than two, straight lines are designed to be essentiallyparallel to each other. The branches can have a short distance from eachother. Studies have shown that, due to the adjacent arrangement, it ispossible to minimize interference due to structural or spatialdifferences; in particular, slight deviations in the parallelism in arange of less than fifteen angular degrees between the two straightlines do not result in a reduction in sensitivity in the arrangementaccording to the invention.

It has proven to be advantageous to select the first plurality of Hallelements and/or parts of Hall elements and the second plurality of Hallelements and/or parts of Hall elements in such a way that a sufficientlyreliable and meaningful measurement result is obtained with the aid ofthe integrative evaluation of the measuring signals, without the numberof Hall elements and the spatial size or complexity for manufacturingbecoming too great. The supply voltage terminals do not necessarily haveto be designed as second terminal contacts. However, the second terminalcontacts as supply voltage contacts are the preferred design, due to theeasy contactability.

Alternatively, one of the supply voltage terminals or both supplyvoltage terminals can contact the electrical connecting line between twoHall elements. In other words, at least one of the supply terminals isprovided between two Hall elements.

In an embodiment, the supply voltage terminals can be disposed in thering of the series-connected Hall elements in such a way that the samenumber of Hall elements and/or parts of Hall elements are disposedbetween the two supply voltage terminals in both branches. This makes itpossible to achieve the desired sensitivity with an uneven number N ofseries-connected Hall sensors.

The number of series-connected Hall elements can be in a range from fourto eighteen, preferably in a range from six to eighteen. With an overalleven number N of Hall elements, a balanced and lessinterference-susceptible Hall sensor is achieved from a large number ofHall elements having a high sensitivity. The implemented number oftwelve series-connected Hall elements has proven to be very advantageousin this connection, since it demonstrates a significant efficiency inthe sense of a high magnetic sensitivity, with a not all too greatstructural complexity of the Hall sensor. The magnetic sensitivityincreases along with the increase in the number N of symmetrical,electrically series-connected Hall element, the increase in low numbersN of Hall elements being greater than the increase in a higher number Nof Hall elements. Studies have shown that the particularly preferrednumber of series-connected Hall elements is in a range from eight tosixteen.

Studies have shown that it is advantageous to select the same number offirst plurality N1 of Hall elements and/or parts of Hall elements assecond plurality N2 of Hall elements and/or parts of Hall elements. Inother words, it is preferable to dispose the supply voltage terminals insuch a way that each of the two branches has the same number ofelectrically series-connected Hall elements and parts of Hall elements.In other words, with the first plurality of Hall elements and/or partsof Hall elements, the first branch demonstrates the same number of Hallelements and/or parts of Hall elements between the supply voltageterminals as the second branch demonstrates with the second plurality ofHall elements and/or parts of Hall elements.

In an embodiment, exactly two middle terminal contacts of the Hallelements are connected to a first differential amplifier, and exactlytwo middle terminal contacts of the Hall elements are connected to asecond differential amplifier, exactly one of the two middle contactsbeing from the first branch and exactly one of the two middle contactsbeing from the second branch. In an embodiment, one of the supplyvoltage terminals is provided between the middle terminal contactsconnected to the first differential amplifier and/or one of the supplyvoltage terminals is provided between the middle terminal contactsconnected to the second differential amplifier.

Moreover, in another embodiment, an integrated multiplexer circuitarrangement can be provided for carrying out a spinning current method,using the supply voltage terminals and the Hall voltage taps, thecircuit arrangement and the Hall elements being monolithicallyintegrated into a shared semiconductor body. It is furthermore preferredto dispose the Hall sensor with the integrated circuit arrangement in asingle shared housing and to implement the electrical contacting of theHall sensor via the shared housing. It is understood that at least fourHall elements are provided on the semiconductor body. All Hall elementsof the Hall sensor may be manufactured in a single manufacturing processwith the aid of the monolithic integration. One advantage is that thespatial arrangement of the Hall elements with respect to each other, aswell as the even or uniform provision of the Hall elements or thesymmetry of the Hall elements with respect to each other and theimproved properties of the Hall sensor according to the invention may bereliably produced.

The interfering offset voltages of the Hall sensor may be particularlyadvantageous reduced hereby, and the sensitivity and reliability of thesensor according to the invention may be increased.

It is furthermore advantageous that the Hall elements are designed asvertical Hall elements and, in particular, as Hall plates. Magneticfield components running in the direction of the semiconductor surfaceare detected with the aid of the present vertical Hall elements.Correspondingly, magnetic field components provided perpendicularly tothe semiconductor surface may be determined with the aid of lateral Hallelements. In a combination of vertical Hall elements and lateral Hallelements, all three components of a magnetic field which areorthogonally oriented with respect to each other may be determined.

In an embodiment, it is provided that the Hall elements are disposed ina first triplet in the first branch and in a second triplet in a secondbranch and in a third triplet in a third branch and in a fourth tripletin a fourth branch, the first triplet and the second triplet measuring afirst component of a magnetic field, and the third triplet and thefourth triplet measuring a second component of the magnetic field, andthe first component being provided perpendicularly to the secondcomponent of the magnetic field. It is advantageous of the four branchesare disposed symmetrically around a shared center of gravity and if eachbranch has the same distance from the center of gravity.

Further scope of applicability of the present invention will becomeapparent from the detailed description given hereinafter. However, itshould be understood that the detailed description and specificexamples, while indicating preferred embodiments of the invention, aregiven by way of illustration only, since various changes andmodifications within the spirit and scope of the invention will becomeapparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description given hereinbelow and the accompanying drawingswhich are given by way of illustration only, and thus, are not limitiveof the present invention, and wherein:

FIG. 1 show a Hall sensor according to the invention, including anannular series circuit of Hall elements having an even number of Hallelements;

FIG. 2 shows a Hall sensor according to the invention, including anannular series circuit of Hall elements having an even number of Hallelements;

FIG. 3 shows a Hall sensor according to the invention, including anannular series circuit of Hall elements having an uneven number of Hallelements;

FIG. 4 shows a Hall sensor according to the invention, including a totalof six Hall elements disposed on a single straight line;

FIG. 5 shows a Hall sensor according to the invention, including a totalof six Hall elements disposed on two straight lines;

FIG. 6 shows a Hall sensor according to the invention, including a totalof n Hall elements disposed on a single straight line;

FIG. 7 shows a Hall sensor according to the invention, including a totalof five Hall elements disposed on a single straight line;

FIG. 8 shows a Hall sensor according to the invention, including a totalof five Hall elements disposed on two straight lines;

FIG. 9 shows a representation of the relationship between the number nof Hall elements connected in series and the magnetic sensitivity;

FIG. 10 shows a representation of the relationship between the offsetvoltage and an applied supply voltage for a Hall sensor having multipleHall elements with the application and without the application of thespinning current method;

FIG. 11 shows an embodiment in the form of a pixel cell arrangement;

FIG. 12 shows a view of a Hall sensor according to the prior art,including a series circuit of four Hall elements; and

FIG. 13 shows a cross section of a Hall element illustrated in FIG. 12according to the prior art.

DETAILED DESCRIPTION

FIG. 1 shows a first embodiment of Hall sensor 10 according to theinvention, which includes eight Hall elements E1 through E8, Hallelements E1 through E8 being electrically connected in series. Hallelements E1, E2, E3, E4, E5, E6, E7 and E8 are designed as vertical Hallelements, the cross section of individual Hall elements E1 through E8being identical to each other. A preferred structure is designedaccording to the prior art and illustrated in detail in FIGS. 12 and 13.In contrast to FIGS. 12 and 13, a top view of the Hall elements providedwithin a semiconductor surface is illustrated in the present case. Thedirection of a magnetic field B to be measured points in a y direction,i.e., the direction of a magnetic field to be measured is in the planeof the drawing or parallel to the semiconductor surface.

Each of Hall elements E1, E2, E3, E4, E5, E6, E7 and E8 has a firstterminal contact 23, 33, 43, 53, 63, 73, 83 and 93 as well as a secondterminal contact 26, 36, 46, 56, 66, 76, 86 and 96 as well as a thirdterminal contact 29, 39, 49, 59, 69, 79, 89 and 99. The series circuitis implemented by the fact that, in each case, third terminal contact29, 39, 49, 59, 69, 79, 89 and 99 is connected to first terminal contact23, 33, 43, 53, 63, 73, 83 and 93 of Hall element E1, E2, E3, E4, E5,E6, E7 and E8 following in the series. This results in a closed ring ofelectrically series-connected Hall elements E1, E2, E3, E4, E5, E6, E7and E8. Second terminal contacts 26, 36, 46, 56, 66, 76, 86 and 96 aredesigned either as supply voltage terminals or as Hall voltage taps. Itshould be noted that, according to one embodiment which is notillustrated, additional Hall elements may be inserted, an insertion ofthe additional Hall elements between third Hall element E3 and fourthHall element E4 or sixth Hall element E6 and seventh Hall element E7being shown in the present case.

Second terminal contact 26 of first Hall element E1 is designed as asupply voltage terminal and is connected to a supply voltage V_(in).Second terminal contact 66 of fifth Hall element E5 is designed asanother supply voltage terminal and is connected to a reference voltageV_(gnd), reference voltage V_(gnd) being designed as a ground potential.Hall voltages +V_(H−1) through +V_(H−n/2) and V_(H+1) through V_(H+n/2),where n equals eight, may be tapped at the other second terminalcontacts 36, 46, 56, 76, 86 and 96.

The closed ring may be divided into a first branch R1 and into a secondbranch R2, the assignment of all Hall elements to one of the twobranches R1 and R2, Hall elements E1, E2, E3, E4, E5, E6, E7 and E8 inthe present case, resulting from the two feeding points for supplyvoltage V_(in) and reference voltage V_(gnd).

First branch R1 has a beginning A1 and an end EN1, end EN1 of firstbranch R1 being connected to a beginning A2 of second branch R2, andbeginning A1 of first branch R1 being connected to an end EN2 of secondbranch R2. As a result, the current direction through the Hall elementsof first branch R1 is counter to the current direction through the Hallelements of second branch 2, and the relation (J1×B)=−(J2×B) applies,where J1 is the current density vector in the Hall elements of firstbranch R1, and J2 is the current density vector in the Hall elements ofsecond branch R2, and B is the vector of an applied magnetic field.

In the present embodiment, the two feeding points are connected tomiddle terminal contacts 26 and 66; in other words, the division intothe two branches R1 and R2 runs exactly through middle terminal contacts26 and 66 of first Hall element E1 and fifth Hall element E5 in eachcase. Correspondingly, a first half of first Hall element E1 is assignedto first branch R1, and the second half of first Hall element E1 isassigned to second branch R2, and in fifth Hall element E5, a first halfis also assigned to second branch R2 and a second half is assigned tofirst branch R1. Moreover, Hall elements E2, E3 and E4 are assigned tofirst branch R1, and Hall elements E6, E7 and E8 are assigned to secondbranch R2. First branch R1 has a number of n=3 Hall voltage taps. Secondbranch R2 has the same number of n=3 Hall voltage taps. First branch R1furthermore includes a first plurality N1 of Hall elements and parts ofHall elements, and second branch R2 includes a second plurality N2 ofHall elements and parts of Hall elements, first plurality N1 being ofthe same size as second plurality N2.

The Hall elements are provided along two different parallel, straightlines. The two branches R1 and R2 are disposed in direct spatialproximity to each other, whereby Hall elements E1, E2, E3, E4, E5, E6,E7 and E8 are subject to comparable external conditions, in particularmagnetic field conditions, and interfering, differentiated effects aresuppressed, in particular during an integrating evaluation of themeasuring signals.

An embodiment of a series circuit of a total of four Hall elements E1through E4 according to the prior art is illustrated in FIG. 12. Each ofHall elements E1 through E4 includes exactly three terminal contacts 23,26; and 29 or 33, 36; and 39 or 43, 46 and 49 or 53, 56 and 59. The twoouter terminal contacts 23, 29 and 33, 39 and 43, 49 and 53 and 59 ofeach Hall element are each connected to outer terminal contacts 23, 29and 33, 39 and 43, 49 and 53 and 59 of the two directly adjacent Hallelements. Two of middle terminal contacts 26, 36, 46 and 56 are designedas supply voltage terminals and two more of middle terminal contacts 26,36, 46 and 56 are designed as Hall voltage taps. Series-connected Hallelements E1 through E4 each demonstrate a symmetrical structure ofterminal contacts 23 through 29, i.e., the two outer terminal contacts23, 29 and 33, 39 and 43, 49 and 53 and 59 of each Hall element have thesame distance with respect to particular middle terminal contact 26, 36,46 and 56 of Hall elements E1 through E4.

A cross section of an individual Hall element according to the prior artis illustrated in FIG. 13 on the basis of the left Hall element in FIG.12, whose structure corresponds to the Hall elements in FIG. 1. The Hallelement is provided with a symmetrical design with respect to a mirrorplane S, which extends in the longitudinal direction through the centerof second terminal contact 26 and thus through the Hall element. Thegeometric dimensions as well as the material composition of all Hallelements of a Hall sensor are selected to be identical or preferablylargely identical.

According to the embodiment illustrated in FIG. 13, the direction of amagnetic field to be measured points in a y direction, i.e., into or outof the plane of the drawing.

FIG. 2 shows a second embodiment of Hall sensor 10 according to theinvention, which includes a total of eight Hall elements E1 through E8.Only the differences from the embodiments explained in connection withthe preceding embodiments are discussed below. In contrast to theembodiment illustrated in FIG. 1, the feeding point for supply voltageV_(in) is on the connecting line between first Hall element E1 andsecond Hall element E2 and not on one of the middle contacts of one ofHall elements E1 through E8. In the same manner, the feeding point forreference voltage V_(gnd) is on the connecting line between fifth Hallelement E5 and sixth Hall element E6 and not on one of the middlecontacts of one of the Hall elements. As a result, end EN1 of firstbranch R1 and beginning A2 of second branch R2 are provided at thefeeding point of reference voltage V_(gnd), and end EN2 of second branchR2 and beginning A1 of first branch R1 are provided at the feeding pointof supply voltage V_(in). The Hall voltage taps are provided on middlecontacts 26, 36, 46, 56, 66, 76, 86 and 96 of Hall elements E1 throughE8.

FIG. 3 shows a third embodiment of Hall sensor 10 according to theinvention, which includes a total of seven Hall elements E1 through E7.Only the differences from the embodiments explained in connection withthe preceding embodiments are discussed below. In contrast to theembodiment illustrated in FIG. 1, the feeding point for referencevoltage V_(gnd) is on the connecting line between fourth Hall element E4and fifth Hall element E5 and not on a middle contact of a Hall element.As a result, end EN1 of first branch R1 and beginning A2 of secondbranch R2 are provided at the feeding point of reference voltageV_(gnd).

FIG. 4 shows a fourth embodiment of Hall sensor 10 according to theinvention, which includes a total of six Hall elements E1 through E6.Only the differences from the embodiments explained in connection withthe preceding embodiments are discussed below. All Hall elements E1through E6 are provided along a single, shared straight line, firstbranch R1 and second branch R2 each including two Hall voltage taps. Thefeeding point for supply voltage V_(in) is on the middle contact ofsecond Hall element E2, and the feeding point for reference voltageV_(gnd) is on the middle contact of fifth Hall element E5.Correspondingly, the left half of second Hall element E2 and first Hallelement E1 and sixth Hall element E6 and the right half of fifth Hallelement E5 are assigned to first branch R1. The right half of secondHall element E2 and third Hall element E3 and fourth Hall element E4 theleft half of fifth Hall element E5 are assigned to second branch R2. Asa result, first plurality N1 of Hall elements and parts of Hall elementsin first branch R1 and second plurality N2 of Hall elements and parts ofHall elements in second branch R2 are of the same size.

As a result of the distribution of Hall elements E1 through E6 to thetwo branches R1 and R2, Hall voltage V_(H−+1) may be tapped at themiddle contact of first Hall element E1, and Hall voltage V_(H−+2) maybe tapped at the middle contact of sixth Hall element E6, and Hallvoltage V_(H+−1) may be tapped at third Hall element E3, and Hallvoltage V_(H+−2) may be tapped at the middle contact of fourth Hallelement E4.

The middle contact of the first Hall element is connected to anon-inverting input of a first differential amplifier DIV1, and themiddle contact of the third Hall element is connected to an invertinginput of first differential amplifier DIV1. The middle contact of thefourth Hall element is furthermore connected to an inverting input of asecond differential amplifier DIV2, and the middle contact of the sixthHall element is connected to a non-inverting input of seconddifferential amplifier DIV2. First differential amplifier DIV1 has oneoutput, and second differential amplifier DIV2 has one output. A firstHall voltage differential signal is available at the output of firstdifferential amplifier DIV1, and a second Hall voltage differentialsignal is available at the output of second differential amplifier DIV2.The two outputs of differential amplifiers DIV1 and DIV 2 are connectedto a summation unit SUM1. The summation unit provides a summation signalat one output, formed from an addition of the first Hall voltagedifferential signal and the second Hall voltage differential signalaccording to the following relation:

V _(HSensor)(V)=Σ_(i=1) ²(V _(H+i) −V _(H−i))

where V_(H+i) represents the Hall voltages ascertained at the middlecontacts of the Hall elements of the first branch, and V_(H−i)represents the Hall voltages ascertained at the middle contacts of theHall elements of the second branch. In the present embodiment, a seriescircuit of one Hall element and/or parts of Hall elements E1 through E3or E4 through E6 is provided between the two inputs of the twodifferential amplifiers DIV1 and DIV2. A supply voltage terminal isfurthermore disposed between the two inputs in each case.

FIG. 5 shows a fifth embodiment of Hall sensor 10 according to theinvention, which includes a total of six Hall elements E1 through E6.Only the differences from the embodiment explained in connection withthe illustration in FIG. 4 are discussed below. The Hall elements aredisposed along two different straight lines which are parallel to eachother. Hall elements E1 through E3 are disposed on the first straightline, and Hall elements E4 through E6 are disposed on the secondstraight line.

FIG. 6 shows a sixth embodiment of Hall sensor 10 according to theinvention, which includes a total of n Hall elements E1 through En,disposed along a single straight line. Only the differences from thepreceding embodiments are explained below. It is understood that theHall elements may be disposed on two or more straight lines according toembodiments which are not illustrated. In the present case, all middlecontacts of the individual Hall elements as well as all connecting linesbetween the individual Hall elements are connected to inputs of amultiplexer unit MUX. Supply voltage V_(in) and reference voltageV_(gnd) are present at additional inputs of multiplexer unit MUX. Theinputs of n/2 differential amplifiers DIV1 through DIVn/2 are connectedto outputs of multiplexer unit MUX. All outputs of differentialamplifiers DIV1 through DIVn/2 are connected to summation unit SUM1.

One advantage of the present embodiment is that the beginning and end offirst branch R1 and second branch R2 may be arbitrarily shifted with theaid of multiplexer unit MUX. Another advantages is that a so-calledspinning current method may be very easily and reliably carried out withthe aid of multiplexer unit MUX. It should be noted that it isadvantageous to monolithically integrate all Hall elements E1 through Eninto a shared semiconductor body, where n is a natural number greaterthan three and, in particular, less than thirty.

FIG. 7 shows a seventh embodiment of the Hall sensor according to theinvention, which includes a total of five Hall elements E1 through E4and E6, disposed on a single straight line. Only the differences fromthe preceding embodiment, explained in connection with the illustrationin FIG. 4, are discussed below. In the present case, Hall element E5 isomitted, and reference voltage V_(gnd) is applied to the connecting linebetween fourth Hall element E4 and sixth Hall element E6.

In contrast to the seventh embodiment, FIG. 8 shows an eighth embodimentof the Hall sensor according to the invention, including a total of fiveHall elements E1 through E4 and E6, disposed on two different straightlines which are parallel to each other.

The relationship between number n of the Hall voltage taps and magneticsensitivity S_(A) in unit mv/T is plotted in FIG. 9

S _(A) =V _(Hsensor) /B=1/BΣ _(i=1) ^(n/2)(V _(H+i) −V _(H−i))

Magnetic sensitivity S_(A) increases along with the increasing number nof Hall voltage taps, the increase being greater at low numbers than athigher numbers. Extensive studies have shown that the preferred numberof Hall voltage taps is particularly advantageous in a range of eight tosixteen. As a result, magnetic sensitivity S_(A) may be greatly elevatedwithout the current flow through the series-connected Hall elementsincreasing. In other words, it has been shown that the load on Hallsensor 10 remains low, according to the invention, with an increase inmagnetic sensitivity S_(A), while the reliability of Hall sensor 10increases.

In particular, an implemented number of n=12 Hall voltage taps hasproven to be very advantageous. As a result, with a number n=12, asignificant efficiency of the Hall sensor is demonstrated in the senseof a high magnetic sensitivity S_(A) and a not excessively highstructural complexity, i.e., in particular a not excessively highutilization of semiconductor area.

FIG. 10 shows a representation of the relationship between offsetvoltage V_(O) in unit μV and a present supply voltage V_(in) in unit Vfor a Hall sensor which includes eight Hall voltage taps when using andwhen not using the spinning current method, in the present case, firstplurality N1 of Hall elements and parts of Hall elements in first branchR1 being equal to second plurality N2 of Hall elements and parts of Hallelements in second branch R2. For reasons of clarity, offset voltageV_(O) is represented by a solid line in each case for positive offsetvoltage +V_(O) and for negative offset voltage −V_(O). One preferredcircuit arrangement for carrying out the method includes a multiplexerunit MUX according to the embodiment illustrated in FIG. 6. It has beenshown that, in a given circuit configuration of the Hall elements, anincreasing positive offset voltage +V_(O) sets in as supply voltageV_(in) increases, represented by a linear progression of first voltageV_(Osp1), or in a given other circuit configuration of the Hallelements, a decreasing negative offset voltage −V_(O) sets in as supplyvoltage V_(in) increases, represented by a linear progression of secondvoltage V_(Osp2).

If the spinning current method and the underlying rotation and summingup of the offset voltages of the individual circuit configurations areused, the result is a progression of offset voltage V_(OaS), the offsetmeasured values after the “spinning” being represented by stars, closeto the zero line, i.e., the offset measured values are all in the areaof 0 μV. This shows that, not only the sensitivity of the Hall sensor isincreased, but the negative influence of a possible offset is alsogreatly reduced, and the Hall sensor facilitates particularly reliableinformation about a magnetic field strength to be measured.

The illustration in FIG. 11 shows a ninth embodiment in the form of apixel cell arrangement. Only the differences from the precedingembodiments are discussed below. The pixel cell arrangement forms a Hallsensor 10 according to the invention, Hall elements (E1, E2, E3, E4, E5,E6, E7 and E8, . . . ) being disposed in a first triplet X1, X2 and X3in first branch R1 and in a second triplet X4, X5 and X6 in secondbranch R2 and in a third triplet Y1, Y2 and Y3 in a third branch R3 andin a fourth triplet Y4, Y5 and Y6 in a fourth branch R4. The fourbranches R1 through R4 are disposed symmetrically around a shared centerof gravity SZ, each of branches R1 through R4 having the same distancefrom center of gravity SZ. Each triplet of the four branches R1 throughR4 includes exactly three vertical Hall elements, the Hall elements offirst triplet X1, X2 and X3 and the Hall elements of second triplet X4,X5 and X6 measuring an x component of a magnetic field, and thirdtriplet Y1, Y2 and Y3 and fourth triplet Y4, Y5 and Y6 measuring a ycomponent of the magnetic field. The x component of the magnetic fieldand the y component of the magnetic field are provided perpendicularlyto each other.

Due to the particularly advantageous pixel arrangement, it is possibleto create a compact unit for a Hall sensor. It is advantageous tomonolithically integrate an evaluating and activating circuit, togetherwith the pixel cell arrangement, on a shared semiconductor substrate ina shared housing. This makes it possible to design a veryeasy-to-handle, in particular compact as well as robust and reliableHall sensor 10.

The invention being thus described, it will be obvious that the same maybe varied in many ways. Such variations are not to be regarded as adeparture from the spirit and scope of the invention, and all suchmodifications as would be obvious to one skilled in the art are to beincluded within the scope of the following claims.

What is claimed is:
 1. A Hall sensor having a plurality of Hallelements, each of the Hall elements having a first terminal contact anda second terminal contact and a third terminal contact, the plurality ofHall elements being electrically connected in series such that the firstterminal contacts and the third terminal contacts of the individual Hallelements are connected to each other, the second terminal contacts ofthe Hall elements being voltage supply terminals or Hall voltage taps,and the second terminal contact of the Hall element being a middlecontact of the Hall element, the Hall sensor comprising: a first branchhaving a first beginning and a first end, the first branch including aseries circuit of a first portion of the plurality of Hall elements; anda second branch having a second beginning and a second end, the secondbranch including a series circuit of a second portion of the pluralityof Hall elements; wherein the first and second branches are electricallyconnected in series, the first end of the first branch beingelectrically connected in series to the beginning of the second branch,and the beginning of the first branch being electrically connected inseries to the end of the second branch such that a direction currentflow through the Hall elements of the first branch is counter to adirection of current flow through the Hall elements of the second branchso that a vector product J1×B=−(J2×B) is fulfilled, where J1 is thecurrent density vector in the Hall elements of the first branch and J2is the current density vector in the Hall elements of the second branchand B is the vector of an applied magnetic field, and wherein at leastfour Hall voltage taps are provided, two of the Hall voltage taps beingarranged in the first branch and two of the Hall voltage taps beingarranged in the second branch and the Hall voltage taps being designedas middle contacts.
 2. The Hall sensor according to claim 1, wherein thefirst branch and the second branch are arranged along a shared straightline or along multiple different straight lines, the multiple straightlines being essentially parallel to each other.
 3. The Hall sensoraccording to claim 1, wherein one of the supply voltage terminals orboth supply voltage terminals is/are provided between two Hall elements.4. The Hall sensor according to claim 1, wherein exactly two middlecontacts of the Hall elements are connected to a first differentialamplifier and exactly two middle contacts of the Hall elements areconnected to a second differential amplifier, and wherein exactly one ofthe two middle contacts is from the first branch and exactly one of thetwo middle contacts is from the second branch.
 5. The Hall sensoraccording to claim 4, wherein one of the supply voltage terminals isprovided between the middle terminal contacts connected to the firstdifferential amplifier or one of the supply voltage terminals isprovided between the middle terminal contacts connected to the seconddifferential amplifier.
 6. The Hall sensor according to claim 1, whereinthe number of Hall voltage taps is in a range between 6 to
 18. 7. TheHall sensor according to claim 1, wherein the first portion of theplurality of Hall elements in the first branch is of a same size as thesecond portion of the plurality of Hall elements in the second branch.8. The Hall sensor according to claim 1, wherein an integratedmultiplexer circuit arrangement is provided for carrying out a spinningcurrent method, and wherein a circuit arrangement and the Hall elementsare monolithically integrated into a shared semiconductor body.
 9. TheHall sensor according to claim 1, wherein the first terminal contactsand the third terminal contacts are arranged symmetrically around thesecond terminal contacts.
 10. The Hall sensor according to claim 1,wherein the Hall elements have an identical structure with respect toeach other.
 11. The Hall sensor according to claim 1, wherein the Hallelements are vertical Hall elements.
 12. The Hall sensor according toclaim 1, wherein the Hall elements are arranged in a first triplet inthe first branch and in a second triplet in a second branch and in athird triplet in a third branch and in a fourth triplet in a fourthbranch, and wherein the first triplet and the second triplet measure afirst component of a magnetic field, and the third triplet and thefourth triplet measure a second component of the magnetic field, andwherein the first component of the magnetic field and the secondcomponent of the magnetic field are substantially perpendicularly toeach other.
 13. The Hall sensor according to claim 12, wherein the fourbranches are arranged symmetrically around a shared center of gravity,and wherein each of the branches has a same distance from a center ofgravity.
 14. The Hall sensor according to claim 1, wherein a total Hallvoltage results from the sum of Hall voltage differences, wherein eachHall voltage difference results from a difference formation of the Hallvoltage at one of the middle contacts of a Hall element of the firstbranch and the Hall voltage at one of the middle contacts of a Hallelement of the second branch.